Automatic pressure switch



Feb. 2, 1932;

77H. L. VAN 'VALKENBURG AUTOMATIC PRESSURE SWITCH Filed Sept. 14, 1 9292 Sheets-I-Sheet 1' I N VEN TOR. 141/7 ATTORNEYS.

Feb. 2, 1932. H. L. VAN VALKENBURG' 3,2

AUTOMATIC PRESSURE swmcn Filed Sept. 14, 1929 2 Sheets-Sheet 2 $5M":INVENTOR.

I: w dg ryrzjruwlz ATTORNEYS.

Patented Feb. 2, 1 932 HEBMON VAIIKENB'UBG, OF WLWATOSA, WISCONSIN,ASSIGNOR TO SQUARE D COMPANY, OF DETROIT,

MICHIGAN, CORPORATION OF MICHIGAN aurom'n'c rnnss unn swrrcn Applicationfled September 14, 1929. Serial No. 392361.

- This invention relates to improvements in automatic pressure switchesfor controlling the operation of. pressure pumps and other devices bypredetermined pressures ofthe me ium pum ed.

It is oneo the objects of the presentinvention to provide an automaticpressure switch having a cam and roller mechanism combined. with atoggle for operating the switch.

' A further object of the invention is to provide an automatic pressureswitch having adjustable spring means for varying the pressure at whichthe switch .will operate.

A further object ofthe invention is to provide an automatic pressureswitch having a latch mechanism for ositively holding the switchmechanism in oth its on posltion and in its oflosition.

A further 0 ject of theinvention is to rovide an automatic pressureswitch in w ich the movable contacts of thecswitch are separated with aquick movement to minimiz arcing between the contacts.

28 A further object of the invention is to rovide an automatic pressureswitch havlng adjustable means controlled by the pressure of the mediumpumped and also having other means for forming a diflerential adjustmentof the parts withrespectto open.- ing and closing the switch,

A further object of the invention is to pro- Vide an automatic pressureswitch having novel means for connecting the diaphragm to the actuatinmechanism.

A further ob ect' of theinvention is to pro- 'vide an automatic pressureswitch which is of simple construction,

and is well adapted scribed.

Withthe above is strong and durable for the purpose deand other objectsin view the invention consists of the improved automatic pressure switchand its parts and combinations as set forth in the claims, and allequivalents thereof.

In the acompanying drawings in which the same reference charactersindicate the same parts in all of the views: -Fig.,.1 is a verticalsectional view -of the improved automatic pressure switch, thetioned bswitch contacts being shown in open position;.,"

n on line 22 of Fig. 1; ig. 3 is a vertical sectional view similar toFig. 1 with the exception that some of the parts have been broken awayto show other parts in the'rear thereof.

Fig. 4 is a vertical sectional view taken on line 4-4 of'Fig. 2, theswitch being shown in closed position; and

Fig. 5 is a fragmentary horizontal sectional view of the'lower portionof the device.

'Referring to the drawings the main-switch housing comprises severalseparable sheetmetal parts. The numeral 8 indicates a U- shaped casingframe having a bottom and integral opposite side walls, 9 the backplate, and 10 the L-shaped top and front cover. The top and front coverside flanges 11 which overla the adjacent rear andtop edge portions 0the side walls of the casing frame 8, and the lower'cover 10 alsooverlaps the upper edgeof the back plate 9. Said cover 10 is-formed witha lower front slot 10 and a screw 12 extending through said slot andthreaded into the frame firmly holds the cover in position. The backplate 9 is also termed with side flanges 13 toreceive F of t F 10 isformed with" ii. 2 is a horizontal sectional view there-- screws 14; forfastening the plate in position.

Said back plate is also provided with apertured brackets 15 for securingthe frame to a support. An insulating block 16 is positween andconnected to the opposite side walls of the frame by screws 17. Electricterminals 18 and 19 mounted on the outer side of the insulating blockare adapted to be connected to wires 20 and 21 which extend to a sourceof current supply. The heads of the bolts 22, which extend through theinsulating block 16 to secure the terminals 18 to the block, serve asfixed contacts for the switch.

Said heads are positioned between insulating guard flanges 23 to preventarcing between two of the switch contacts.

A switch block of insulating material pivotally connected to the frame 8by a pin 25 is provided with a pair of angled switch arms 26 which areadapted to contact with the fixed contacts 22 when swung to their 01pins 30 extending through the arms and block 24 have'surrounding'springs 31 which are interposed between the block andcaps 33 casinframe. The roller 52 is ieldingly held in enga ement with the angu arend53 by means 0 a differential coiled spring 55 which is connected atits lower end to the inner edge of the arm 46. The upper end of thespring is connected to a screw member 56'which extends loosely throughthe arm 51 and above the'arm is engaged bya nut 57 to rovide for the;difi'erential adjustment of t e tripping mechanism. The lower pormountedon the pins to yieldingly hold the tion of the nut has-a knife'edge andthe upswitch arms on the block.

Flexible electrical connectors 34 connect the lower end portions of theswitch arms to the lower terminals 19.

v A diaphragm or actuator casing 35 mountper portion of the bifurcatedarm is formed with a groove as indicated by the numeral .51 to hold thenut in adjusted osition. The lower end of the lever 54 is ormed with aslot 58 to receive the pin 59 -ofan angular ed on the lower portionlofthe frame is pro lever which is fulcrumed on the inner side vided with aflexible diaphragm 36 which is engaged by a piston plate 37 having threepiston pins 38. The pins extend upwardly and. loosely through thediaphragm casing and the bottorfi .portion of the frame and have upperreduced diameter end portions forming shoulders 38'; The lower portionof the diaphragm casing is formed with a threaded opening for receivinga pipe 39 which is'connected to the sourceof pressure tobe controlled:

vA stud bolt or standard 40 riveted to the bottom portion of the casingframe centrally of the diaphragm casing and extending up- -wa rdlytherefrom has a nut 41' threaded on its upper end which bears against-ashouldered collar 42 surrounding the standard. A large coiled spring 43surrounds the standard and a portion of the collar and is interposedbetween the collar and a late member 44 which extends loosely around thestandard and engages the reduced end ortions of the piston pins 38.Triangular s aped washers 45 mounted on the reduced end portions of thepins 38 are interposed between the shoulders 38' of said pins and thelowerside of the plate member 44 to permit vertical adjustment of'theplate member 44 by adding or removing washers from the pins 38. Upwardlyprojecting lips 44 hold the lower end of the spring in position on theplate.-

A bell. crank lever 46 is formed with spaced lower short arms 47 whichstraddle the opposite side edge portionsof .the plate member 44 and arepivotally connected to downwardly angled portions 48 thereof by pivotscrews 49. The lower portion of the bell crank lever is pivoted to thecasing frame by a headed pivot in 50 having a cotter pi-n at one end.The 1 ng arm 46 of the bell crank lever extends upwardly from one of theshort arms 47 and is pivotally" connected between the bifurcations of a.bifurcated arm 51 "which extends outwardly therefrom. A grooved roller52 journaled between the bifurcations of the outer end of said arm 51rides on the of the casing frame. The pin 59 is so posisaid block toswing the switches thereof toon or off position. The pivot pin 63 whichis fulcrumed on the inne r side of the which connects the link 62 to thelever 60 pro- Jects outwardly therefrom and through a segi/ mental slot64, the opposite end portions of which serve as stops to limit themovement of the lever 60.

In operation and with the parts in the position shown in Fig. 4 thepressure in the system to which the switch is connected is 1ndicated asbelow normal and the diaphragm is in its lower position and the switchesare in their on position to run the motor and pumpto increase thepressure in the system. As soon as the pressure reaches thepredetermined amount itwill overcome the pressure of the large spring-43and force the diaphragm, the piston plate and pins and the plate member44-upwardly. This movement will tilt the short arms 47 upwardly and thelong arm 46 to the right or outwardly. This outward movement of the longarm. will, while maintaining the switch firmly in closed position, pullthe grooved roller upwardly on the angled or cam end 53 of the lever 54until the roller asses over the oint of the lever. The di erentialspring w ich has been placed under tension by the upward swing of thearm 51 can now ull the roller downwardly on the right hand angle of thelever and this movement will 'swin' the upper end of the lever to theleft an the lower end. to the .right. This movement will swing the lever60.50 the right and pull the switches to their oil or open position, asshown in Fig. 3, with a quick positive movement to reduce arcing to theminimum. As this movement will swing the pivotal connection 59 towardthe right as viewed in Fi 4, past the plane 'of the axes of the centrapivot of the lever 54 said cam lever, a link connecting and" of the vautomatical y locked in oil or open position. It will be noted that inall positions of the arts upto the instant of breaking the circuit thatthe contacts will be firmly held in engagement with each other. When thefluid pressure decreases below a predetermined-* extent the pressure ofthe large spri1fg'43will force the short arms of 9 the oell crank leverdownwardly and the long arm to the right inwardly, referring to Fig. 3,and this movement 'will cause the roller to ride upthe outer angle ofthe lever 54. As soon as the roller passes over the point of the lever54 the small or differential spring 55 will pull'the arm 51 downwardlyand this movement will swing the lever 54.to close the switches. Thelarge spring Q the pressure at which the diaphragm will move. Forinstance, the large spring will turn the, switches ofi when the pressurereaches 50 pounds, and turn the switches on when the pressure drops to40 any adjustment of this spring will increase or decrease the pressurewithout changing this ten pound range whether themaximum sure is poundsor more or less. On the other hand, the smaller ordifi'erential springcontrols the rangeof opening and closing of the switch. If the range isten pounds under oneadjustment of the differential spring, by increasingthe tension ofthe springthe range may be increased 35 to 15 or 20 poundsor more, an if the spring tension is decreased the range may be ecreased to 3 to 5 pounds, thus providing for in 51 and the switches willhe provides for controllingpounds and prespressure between, the

2. In combination, a frame, a diaphragm supported by said frame, amovable switch element carried by said frame, a bell crank leveriulcrumed on said frame and movable by said diaphra m, a link carried bysaid bell crank lever, and aving a roller secured thereto remotefromsaiol lever, a cam lever fulcrumed on said irarne and engaged atoneend by said roller, a crank lever ulcrumed on said frame and having apair of arms one of which is pivotally and slidably engaged by -theother end oi said cam lever, a connection between the other arm of saidcrank lever and said switch elementgand-a spring connecting said beilcrank lever and said in link, said spring being positioned to maintamthe connection between said cam lever mon plane of In testimony whereof,I afiix my si ature. HERMON L. VAN VALKENB 'the differential adjustmentof the operating pressures in a very simple manner.

From the foregoing description it will be seen that theautomaticpressureswitch is well adapted for the purpose described. What I claim as myinvention is 1. In combination, a frame, a diaphragm supported by'saidframe, a movable switch element carried by said frame, a bell cranklever fulcrumed onsaid irame and having short and long arms,'meansconnecting said diaphragm tosaid short arm, a link pivotally 5 connectedto said long arm and roller secured to the swinging end thereo a camlever fulcrumed at its medial portion on.

said frameand engaged at one end by said roller, a crank leverfulcrumed'on said frame and having two arms one of-which is pivotallyand slidably engaged by the opposite end of the other arm of said cranklever'with said switch element, and a spring connecting thelong arm ofsaid ball crank lever with said roller supporting link, said springbeing positioned tomaintam the connection between said cam lever andsaid cranklever on one side of the common lane of thelpivots oftheselevers when sai switch element is in open position.

havin a."

roller support and said crank lever on one side of the comthe pivots ofthese levers when said switch element is in open position.

